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| United States Patent |
5,005,355
|
|
Singh
|
*
April 9, 1991
|
Method of suppressing formation of contrails and solution therefor
Abstract
A method of suppressing the formation of contrails from the exhaust of an
engine operating in cold temperatures including the steps of providing a
combined nucleating agent and freeze-point depressant selected from the
group of water soluble monohydric, dihydric, trihydric or other polyhydric
alcohols, or mixtures thereof, forming the solution into a vapor, and
injecting the solution into the exhaust of the engine. The solution may
include a non-corrosive surfactant. Another solution may include an
organic or an inorganic nucleating agent, or mixtures thereof, in
monohydric, dihydric or polyhydric alcohols, or mixtures thereof, and in
addition may contain one or more surfactants.
| Inventors:
|
Singh; Surjit (Williamsville, NY)
|
| Assignee:
|
Scipar, Inc. (Williamsville, NY)
|
| [*] Notice: |
The portion of the term of this patent subsequent to August 30, 2005
has been disclaimed. |
| Appl. No.:
|
235670 |
| Filed:
|
August 24, 1988 |
| Current U.S. Class: |
60/204; 60/264; 239/2.1; 239/8; 252/70; 516/114 |
| Intern'l Class: |
F02K 003/04; C09K 003/18; B01D 007/02 |
| Field of Search: |
252/358,321,319,70
239/8,2.1
60/273,282,264,204
|
References Cited
U.S. Patent Documents
| 2835530 | May., 1958 | Schneider | 299/28.
|
| 2908442 | Oct., 1959 | Stone | 239/2.
|
| 2962450 | Nov., 1960 | Elod et al. | 252/319.
|
| 3032971 | May., 1962 | Shotton | 60/205.
|
| 3096290 | Jul., 1963 | Duane et al. | 252/70.
|
| 3289409 | Dec., 1966 | Schirmer | 60/205.
|
| 3429507 | Feb., 1969 | Jones | 239/2.
|
| 3517505 | Jun., 1970 | Anderson et al. | 60/39.
|
| 3517512 | Jun., 1970 | Anderson et al. | 60/264.
|
| 3537900 | Nov., 1970 | Halbert | 134/42.
|
| 3608810 | Sep., 1971 | Kooser | 239/2.
|
| 3608820 | Sep., 1971 | Kooser | 239/2.
|
| 3630913 | Dec., 1971 | Scott, Jr. et al. | 252/70.
|
| 3647710 | Mar., 1972 | Stange | 252/319.
|
| 3722815 | Mar., 1973 | Moore | 239/2.
|
| 3802624 | Apr., 1974 | Kuhne et al. | 239/2.
|
| 3804328 | Apr., 1974 | Lane et al. | 239/2.
|
| 4176790 | Dec., 1979 | Osorio | 239/2.
|
| 4335980 | Jun., 1982 | DePriester | 405/217.
|
| 4358389 | Nov., 1982 | Konig-Lumer et al. | 252/70.
|
| 4362271 | Dec., 1982 | Montmory | 239/2.
|
| 4766725 | Aug., 1988 | Singh | 252/321.
|
| 4808235 | Feb., 1989 | Woodson et al. | 252/170.
|
Other References
J. L. Schmitt et al., Binary nucleation of ethanol and water, J. Chem.
Phys., vol. 92, No. 6, 15 Mar. 1990.
|
Primary Examiner: Lovering; Richard D.
Assistant Examiner: Metzmaier; Daniel S.
Attorney, Agent or Firm: Gastel; Joseph P.
Claims
I claim:
1. A method of suppressing the formation of contrails from water vapor in
the hot exhaust gases of an engine operating in cold temperatures
comprising the steps of providing at least one alcohol which is a combined
nucleating agent and freezing point depressant, and injecting said alcohol
into said hot exhaust gases of said engine for reducing ice particles
formed from said water vapor to a size below a humanly visible range.
2. A method as set forth in claim 1 including the step of forming said
alcohol into a vapor before said step of injecting said alcohol into said
exhaust.
3. A method as set forth in claim 1 wherein said at least one alcohol is
selected from the group consisting of monohydric, dihydric and trihydric
alcohols.
4. A method as set forth in claim 1 including an organic nucleating agent
in solution with said alcohol.
5. A method as set forth in claim 4 wherein said alcohol combined
nucleating agent and freezing point depressant is present in an amount by
weight of between about 25% and 99.9%, and wherein said organic nucleating
agent is present in an amount by weight of between about 0.001% and
saturation.
6. A method as set forth in claim 4 wherein said alcohol is present in an
amount by weight of between about 80% and 99%, and wherein said organic
nucleating agent is present in an amount by weight of between about 0.001%
and saturation.
7. A method as set forth in claim 4 wherein said alcohol is present in an
amount by weight of between about 95% and 99%, and wherein said organic
nucleating agent is present in an amount by weight of between about 0.001%
and saturation.
8. A method as set forth in claim 4 wherein said organic nucleating agent
is selected from the group consisting of phloroglucinol,
ethylenediaminetetraacetate, and catechol.
9. A method as set forth in claim 1 wherein said alcohol is selected from
the group consisting of a glycol, glycerol and polyol.
10. A method as set forth in claim 1 wherein said alcohol is selected from
the group consisting of methanol, ethanol, 2-propanol, 1-propanol,
ethylene glycol, diethylene glycol, thiethylene glycol, tetraethylene
glycol and glycerol.
11. A method as set forth in claim 1 wherein said alcohol is ethylene
glycol.
12. A method as set forth in claim 1 wherein said alcohol comprises a
mixture of plurality of alcohols.
13. A method as set forth in claim 4 including a non-corrosive surfactant.
14. A method as set forth in claim 13 wherein said non-corrosive surfactant
is selected from the group consisting of nonionic, cationic, anionic, and
zwitterionic surfactants.
15. A method as set forth in claim 13 wherein said surfactant is present by
weight in an amount of between about 0.001% to saturation.
16. A method as set forth in claim 13 wherein said surfactant is present by
weight in an amount of between about 0.07% and 20%.
17. A method as set forth in claim 13 wherein said surfactant is present by
weight in an amount of between about 0.1% and 5%.
18. A method as set forth in claim 13 wherein said non-corrosive surfactant
is a sulfonate.
19. A method as set forth in claim 1 including in sufficient proportions
with said alcohol to effect said hypernucleation a sulfonate with an
unsubstituted mono or polysubstituted carbon chain.
20. A method as set forth in claim 1 including in sufficient proportions
with said alcohol to effect said hypernucleation a carboxylate with an
unsubstituted mono or polysubstituted carbon chain.
21. A method as set forth in claim 1 including in sufficient proportions
with said alcohol to effect said hypernucleation an alcoholate with an
unsubstituted mono or polysubstituted carbon chain.
22. A method as set forth in claim 1 including in sufficient proportions
with said alcohol to effect said hypernucleation a phosphate with an
unsubstituted mono or polysubstituted carbon chain.
23. A method as set forth in claim 19 including an organic nucleating
agent.
24. A method as set forth in claim 20 including an organic nucleating
agent.
25. A method as set forth in claim 21 including an organic nucleating
agent.
26. A method as set forth in claim 22 including an organic nucleating
agent.
27. A method as set forth in claim 4 including an inorganic nucleating
agent.
28. A method as set forth in claim 27 wherein said inorganic nucleating
agent is selected from the group consisting of ammonium fluoride, ammonium
iodide, ammonium chloride, calcium chloride, silver iodide, ammonium
thiorcyanate, cadmium iodide, chromium bromide, cobalt iodide (.alpha.),
ferric chloride, tin halides, bismuth trichloride, and thalium chloride.
29. A method as set forth in claim 27 wherein said inorganic nucleating
agent is present by weight in an amount of between about 1% and
saturation.
30. A method as set forth in claim 27 wherein said inorganic nucleating
agent is present by weight in an amount of between about 2% and 12%.
31. A method as set forth in claim 27 wherein said inorganic nucleating
agent is present by weight in an amount of between about 3% and 7%.
Description
BACKGROUND OF THE INVENTION
The present invention relates to an improved method and composition for
suppressing the formation of contrails from the exhaust of an engine, and
is an improvement over the subject matter of U.S. Pat. No. 4,766,725,
issued August 30, 1988.
By way of background, attempts have been made previously to suppress the
formation of contrails from the exhaust of a jet engine. Pat. Nos.
3,517,505 and 3,517,512 teach the injection of chlorosulfonic acid into
the exhaust of an engine to diminish the particle size of water below the
visible range. However, this substance is extremely corrosive. Pat. No.
3,289,409 teaches the injection of carbon black into an aircraft engine
effluent Numerous other patents teach the dispelling of fogs and clouds by
dispersing various compounds therein. However, insofar as known, the
various compounds or components thereof which were used for fog dispersal
were never considered for use in suppressing the formation of contrails
from engines operating in cold environments at high altitudes.
SUMMARY OF THE INVENTION
It is one object of the present invention to provide an improved method of
suppressing the formation of contrails from the exhaust of an engine in a
highly efficient manner.
Another object of the present invention is to provide improved solutions
for suppressing the formation of contrails from the exhaust of an engine
and which can be produced simply and economically and which are not
combustible or corrosive. Other objects and attendant advantages of the
present invention will readily be perceived hereafter.
The present invention relates to a method of suppressing the formation of
contrails from the hot exhaust gases of an engine operating in cold
temperatures comprising the steps of providing in relatively sufficient
proportions any monohydric, dihydric, trihydric, or polyhydric alcohol, or
mixtures thereof, with a compatible surfactant or surfactants or other
compounds capable of exhibiting surface properties in any alcohol,
-diol(glycol), -triol, or polyol, which include their homologues or
general structural relatives, such as their condensation polymers in any
form, and injecting such solution into said exhaust of said engine to
effect hypernucleation of water in the said engine exhaust and lower the
ultimate freezing point of overall exhaust mixtures.
The present invention also relates to a hypernucleating solution for
condensing water vapor in engine exhausts to particles having a size below
the humanly visible range comprising an alcohol solution for effecting
hypernucleation and freezing point depression selected from the group of
monohydric, dihydric, polyhydric alcohols, or mixtures thereof, and which
may have other functional groups or structural features, such as
substituents, unsaturation, and complexation of carbon chains.
The present invention also relates to a method of suppressing the formation
of contrails from the hot exhaust gases of an engine operating in cold
temperatures to particles having a size below the humanly visible range
comprising the steps of providing an alcohol from the group of monohydric,
dihydric, polyhydric alcohols, or mixtures thereof, and which may have
other functional groups or structural features, such as substituents,
unsaturation, and complexation of carbon chains, injecting into said
exhaust gases to effect hypernucleation and freezing point depression of
said water vapor.
The present invention also relates to a hypernucleating solution for
condensing water vapor in engine exhaust to particles having a size below
the humanly visible range comprising in relatively sufficient proportions
to effect said hypernucleation a non-corrosive surfactant in a combined
carrier and nucleating agent selected from the group of water soluble
monohydric, dihydric or polyhydric alcohols, or mixtures thereof, which
may have other functional groups or structural features, such as
substituents, unsaturation, and complexation of carbon chain.
The present invention also relates to a method of preparing a contrail
suppressing solution for effecting hypernucleation of the exhaust of an
engine comprising the steps of dissolving a non-corrosive surfactant in a
minimum amount of water while heating said water to obtain a molecular
solution, heating a small amount of ethylene glycol to boiling, forming a
combined solution of said molecular solution and said small amount of
ethylene glycol and permitting cooling thereof, and adding a final amount
of ethylene glycol to dilute said combined solution, when surfactants
themselves may be somewhat less soluble in glycol.
The present invention also relates to a method of suppressing the formation
of contrails from the hot exhaust gases of an engine operating in cold
temperatures comprising the steps of providing in relatively sufficient
proportions to effect hypernucleation of water in said engine exhaust a
solution of an organic freezing point depressant and nucleating agent, or
a mixture of organic and inorganic freezing point depressants and
nucleating agents, and a combined carrier and nucleating agent and
freezing point depressant selected from the group of water soluble
monohydric, dihydric, trihydric and polyhydric alcohols, or derivatives
thereof, or mixtures thereof, and injecting said solution into said
exhaust of said engine.
The various aspects of the present invention will be more fully understood
when the following portions of the specification are read.
The solution of the present invention includes a biodegradable low suds
non-corrosive surfactant or synthetic detergent which could belong to any
of the major categories, such as nonionic, cationic, anionic, or
zwitterionic or other compounds containing structural features which could
mimic surfactant properties and which will resist oxidation or
decomposition in the hot exhaust gas atmosphere of an engine, which may be
a gas turbine engine, turbojet engine, turbofan engine or rocket engine,
and which will reduce the surface energy of water in the hot exhaust gas
to promote hypernucleation. One such surfactant is obtainable under the
trademark SPARKLEEN.RTM. and is manufactured by the Calgon Corporation of
Pittsburgh, Pennsylvania. It is a sodium alkylsulfonate (C.sub.12) and/or
(C.sub.5 -C.sub.16).
A number of other chemical companies, such as Air Products, Inc., Dow
Chemical, E.I. DuPont, Emery Chemicals, G.A.F. Chemical Corporation,
Pittsburgh Paints, and others manufacture a number of surfactants and
market them under their trade names. At least one member of each category
was tried in the laboratory to prove overall generic nature of the
process. A number of these surfactants are listed by their trade names and
structural features in the following table, and the companies are listed
in alphabetical order. The list is by no means all inclusive and is
offered to illustrate the wide range of surfactants which can be used in
the current application.
______________________________________
Company Name
Trade Name Structural Features
______________________________________
Air Products, Inc.
DH Unsaturated diols
SURFYNOL Series
Unsaturated -ols and
diols, etc.
SVS Unsaturated sulfonates
Dow Chemical
DOWFAX Series Sulfonic salts of
phenyl ethers
E. I. DuPont
ALKANOL Series Alkylaryl
sulfonates
DUPANOL Series Alkyl, alkenyl
sulfonates
ZONYL Series* Fluorosubstituted,
sulfonates, phosphates,
quarternary
ammonium salts
Emery Industries
EMSORB Series Esters
EMERESTAT Series
Polyethylene glycols
derivatives
TRYCOL Series Alcohols, diols, triols,
etc.
TRYMEEN Series Ethoxylated amines
EMERSAL Series Sulfonic salts
G.A.F. Chemicals
Taurine-22 Series
Aminosulfonates
Isethionic Acid
Hydroxysulfonates
SVS Unsaturated sulfonates
Henekel DUO-CURE Series
Proprietary
Morton Thiokol
Ethanesulfonic 2-C Chain sulfonate
Acid
Pittsburgh Paints
Alkyl Sulfonates
Alkyl sulfonates
Alkyl Amines Alkyl amines
______________________________________
*These are listed in greater detail in U.S. Pat. No. 4,766,725, and are
incorporated herein by reference.
Any of the above-listed surfactants or mixtures thereof may be present in
an amount by weight of between about 0.001% to 80% or saturation, and more
preferably between 5% and 30% and most preferably between 10% and 20%, or
the critical micelle concentrations.
Another component of the solution is a water miscible monohydric, dihydric,
trihydric or other polyhydric alcohol or mixtures thereof, which include
their homologs, or general structural relatives, such as their
condensation polymers in any structural form or functional groups, such as
substituents, unsaturation, and complexation of carbon chains, or
derivatives thereof. All of the foregoing are considered hereafter to be
covered under the general term alcohols, glycols, etc. where they are not
specifically mentioned by name. The above-mentioned alcohols can
themselves be used individually without surfactants, as set forth in
greater detail hereafter, or as mixtures by themselves without
surfactants, in contrail suppressing solutions, though, when used
individually or in combinations, they are not as efficient as
alcohol-surfactant mixtures. For example, when the alcohol is ethylene
glycol, it can be used by itself, or when it is used in solution with
other components, such as surfactants, it could present from 10% to 99% in
a contrail suppression solution or, more preferably, 30% to 90% or most
preferably, 75% to 85%. The relative amount of each component is
determined by the molecular structure of alcohol, its freezing point,
chemical nature of the surfactant or surfactant mixtures, and the
solubility of the organic or inorganic nucleating agents. When some of the
surfactants such as the above listed G.A.F. chemicals are used in solution
with ethylene glycol, the solution also contains a small amount of water.
The water may be present in an amount by weight of between about 0.01% and
15%, and more preferably between about 1.5% and 10%, and most preferably
between about 1.7% and 4%. The water is necessary for dissolving the
G.A.F. chemicals and certain other of the above-listed chemicals, such as
SVS, TRYCOLS, isethionic acid, Taurine-22, etc., according to the
following exemplary procedure. Into 5 grams of water, which is a small
amount, 0.13 to 30 grams of the above-mentioned surfactants are poured
into 5 to 30 ml of hot water. The mixture was heated and was boiled for
five minutes to produce a molecular solution which was clear. 10 to 100
milliliters of ethylene glycol were then heated to a boil and the boiled
water solution of the above-mentioned surfactants was poured into the
boiled ethylene glycol while both were at boiling temperature. This amount
of ethylene glycol may otherwise be within 5% and 20% of the total weight
of the mixture at this stage. This mixture is stirred thoroughly until
clear and thereafter cooled. The resulting solution was then diluted to
100 to 250 milliliters by the addition of ethylene glycol. The foregoing
procedure is not required with the surfactants which are easily soluble in
ethylene glycol or other alcohols. The water carrier may be unnecessary
for surfactants which are completely soluble in alcohols, glycols, etc.
Where the surfactant is completely soluble in the alcohol, no special
procedure is required for the mixing operation. It is merely necessary to
add the components and stir them.
When the surfactants were sulfonates or phosphates and were not readily
soluble in alcohol, the surfactants were dissolved in a minimum amount of
boiling water with constant stirring, and the glycol or alcohol was added
in installments to obtain as clear a solution as possible of the desired
concentration. In other instances, alcohol, glycol, diethylene glycol,
triethylene glycol, tetraethylene glycol, or polyethylene glycols or
polyols were heated separately to boiling and added when hot to the slurry
of the surfactant. The mixture was gently heated and continuously stirred
until a clear solution was obtained. Extremes of concentrations of
surfactants used were from 0% to 79% when surfactants were nonionic diols
or ammonia derivatives. Though all water soluble alcohols were
efficacious, formulations were made with methanol, ethanol, 1-propanol,
2-propanol, allyl alcohol, ethylene glycol, diethylene glycol, triethylene
glycol, tetraethylene glycol, polyethylene glycol, glycerol, etc., and
their mixtures. It will be appreciated that the method of preparation may
involve any specialized dissolution, known in the art, of any appropriate
surfactant in ethylene, di, tri, tetra, and polyethylene glycols or
monohydric alcohols, such as methanol, ethanol, 1 and 2 propanol, allyl
alcohol, or triols, polyols, or mixtures thereof.
Solutions were also formulated by mixing any one of the non-corrosive
surfactants with alcohols. In this respect, the solution contained
approximately 0.001% to saturation of the non-corrosive surfactant in an
alcohol, such as ethanol, methanol, isopropanol, propanol, allyl alcohol,
etc., or mixtures thereof. In such solutions the non-corrosive surfactant
may be present by weight in an amount of between about 0.001% and
saturation, and more preferably in an amount of between about 0.07% and
20%, and most preferably in an amount of between about 0.1% and 5%. Any of
the alcohols, or mixtures thereof, listed previously in this
specification, may be present by weight in an amount of between about 25%
and 99.9%, and more preferably in an amount of between about 80% and 99%,
and most preferably in an amount of between about 95% and 99%,
respectively. If desired, a small amount of water or glycerol may be added
to the solution to make up a total of 100%. The combined carrier,
nucleating agent, and freezing point depressant may be any one of the
monohydric, dihydric, trihydric or polyhydric alcohols or mixtures thereof
to produce the total alcohol content.
The hypernucleating solution may also contain mixtures of any of the
above-discussed surfactants such that the total amount of surfactant falls
within the above ranges given for a single surfactant.
The nucleating ability of all of the above mentioned solutions is further
enhanced by adding inorganic or organic nucleating compounds, or mixtures
thereof, which are also freezing point depressants. The inorganic
compounds may be ammonium fluoride, ammonium iodide, ammonium chloride,
calcium chloride, silver iodide, ammonium thiocyanate, cadmium iodide,
chromium bromide, cobalt iodide (.alpha.), ferric chloride, tin halides,
bismuth trichloride, thalium chloride, or other water, alcohol, and glycol
soluble salts. The organic nucleating compounds may be chemicals, such as
phloroglucinol, ethylenediaminetetraacetate, catechol and others which
have ready made hydrogen bonding centers in their molecular structure and
possess straight, side chain, cyclic, or chelic structures which will
facilitate the initial formation of pre-nucleation clusters. The added
components listed above are hygroscopes or nucleating agents preferably
with ice-compatible crystal structures and thermodynamic properties, such
as volatilization, sublimation or boiling temperatures, solubility or
surface energy reduction compatible with those of the surfactant mixtures
of alcohols and/or glycols and/or polyols. Other compounds meeting any or
all of the foregoing criteria can also be used as additives. The ability
to form a eutectic is desirable but not necessary. A mixture may contain
by weight 1% to saturation of the salt or organic compound and more
preferably may contain 2% to 12% thereof and most preferably may contain
3% to 7% thereof. The mixture would include a monohydric, dihydric,
trihydric and/or a polyhydric alcohol or mixtures thereof. The weight
percent of salt or organic compound, or mixtures thereof, is also governed
by its overall molecular weight, e.g., a much greater weight percent of
silver iodide would be needed compared to ammonium fluoride because molar
weight of silver iodide (AgI) is 235 while that of ammonium fluoride
(NH.sub.4 F) is only 37. All of the above inorganic and organic nucleating
compounds are completely soluble in the alcohol-surfactant mixtures and
therefore no special procedure is necessary for mixing them.
When the inorganic or organic nucleating agent, or combinations thereof, is
added in the foregoing amounts, the other components of the solution are
reduced proportionately. For example, the surfactant, or combinations
thereof, may be present by weight in an amount of between about 0.001% and
50% and the combined carrier and nucleating agent, or combinations
thereof, may be present in an amount between about 30% and 98% when the
inorganic or organic nucleating agent, or combinations thereof, is present
in an amount of between about 1% and 20%. Furthermore, and more
preferably, the surfactant may be present in an amount of between about
0.06% and 25% and the combined carrier and nucleating agent may be present
in an amount of between 68% and 97% when the inorganic or organic
nucleating agent is present in an amount of between about 2% and 12%.
Furthermore, and most preferably, the surfactant may be present in an
amount of between about 0.1% and 10% when the combined carrier and
nucleating agent is present in an amount of 2% and 90% when the inorganic
or organic nucleating agent is present in an amount of between 3% and 7%.
Any one of the above-mentioned inorganic salts or organic nucleating
compounds, or mixtures thereof, may be added to any one of the
above-mentioned alcohols, or to mixtures thereof, without the addition of
surfactants. In this respect the salt or compound, or mixtures thereof,
could be present in an amount by weight of between about 1% and 20%, and
more preferably between about 2% and 12%, and most preferably between
about 3% and 7%. The remainder of the mixture would be any one of the
above-mentioned alcohols, or mixtures thereof, either full strength or
diluted with water. The hypernucleating solution thus formed would be
operative, but not as effective as mixtures containing a surfactant in the
sense that much greater amounts would be required. No special procedure is
necessary for combining the alcohol and inorganic salt or organic
nucleating compound, or mixtures thereof, other than mixing them.
The component of the solution to which the non-corrosive surfactant is
added is both a carrier and a nucleating agent which may fall within the
class of water soluble monohydric, dihydric, trihydric and polyhydric
water miscible alcohols, which include the above-discussed alcohols
including ethanol, methanol and ethylene glycol and glycerol, all of which
are also freezing point depressants.
In use, the solution is preferably injected in vapor form into the exhaust
gases of a jet engine, but it may be sprayed into the exhaust in liquid
form. It may be formed into a vapor by suitable heating or spraying or by
any other suitable mode of vaporization, such as air atomization. The
exhaust gases leave the jet engine at about 950.degree. F. (about
450.degree. C.), and pass through an exhaust pipe before they enter a high
altitude low pressure environment wherein the temperature is as low as
-50.degree. C. The hypernucleation solution is injected into the exhaust
gases in the exhaust pipe. The injected solution of the present invention
produces hypernucleation of the water vapor in the exhaust gases while
they are in the exhaust pipe about to exit into the atmosphere because the
injected solution lowers the surface energy requirements for droplet
formation. In addition, the solution depresses the freezing point. The
hypernucleation and freezing point depression cause the formation of ice
crystal structure sizes which are outside of the humanly visible range,
namely, between 0.01 and 0.2 microns, when the jet engine operates in the
cold low pressure environments which are experienced at high altitudes.
In laboratory testing it was found that the amount of hypernucleating
solution of the present invention which can be injected into the engine
exhaust gases may be by weight between about 1% and 25% of the weight of
the jet fuel, and more preferably between about 3% and 15%. Actual tests
were performed wherein the amount of hypernucleating agent of the present
invention which was used was about 12% of the weight of the jet fuel which
was consumed. The foregoing applies to hypernucleating solutions which do
not include the above-mentioned inorganic nucleating agents. However, when
hypernucleating solutions which include the inorganic or organic
nucleating agents, or mixtures thereof, are used, the amount required is
reduced to about 40% of the amount of solutions which do not include the
inorganic agent. The exact amount of hypernucleating agent which is used
will be controlled by the pilot of the aircraft and it depends on plane
altitude and various meteorological factors such as temperature,
atmospheric pressure and relative humidity.
EXAMPLES OF SOLUTIONS WHICH PROVED SATISFACTORY IN THE LABORATORY TO THE
VISUALLY PERCEPTIBLE RANGE THUS CAPABLE OF SUPPRESSING CONTRAILS
The examples are given under functional group tables representing only a
few of the many possible combinations.
TABLE I
__________________________________________________________________________
EXAMPLES OF ALCOHOLS, DIOLS AND POLYOLS
PERCENT OF SOLUTION BY WEIGHT
REAGENT
1 2 3 4 5 6 7 8 9 10 11 12 13
__________________________________________________________________________
Methanol
100
0 0 0 0 0 0 0 0 0 0 0 a
Ethanol
0 100
0 0 0 0 0 0 0 0 0 0 b
2-Propanol
0 0 100
0 0 0 0 0 0 0 0 0 c
1-Propanol
0 0 0 100
0 0 0 0 0 0 0 0 d
Other 0 0 0 0 100
0 0 0 0 0 0 0 e
Alcohols
Ethylene
0 0 0 0 0 100
0 0 0 0 0 0 f
Glycol
Diethylene
0 0 0 0 0 0 100
0 0 0 0 0 g
Glycol
Triethylene
0 0 0 0 0 0 0 100
0 0 0 0 h
Glycol
Tetraethylene
0 0 0 0 0 0 0 0 100
0 0 0 i
Glycol
Any Glycol
0 0 0 0 0 0 0 0 0 100
0 0 j
Glycerol
0 0 0 0 0 0 0 0 0 0 100
0 k
Any Polyol
0 0 0 0 0 0 0 0 0 0 0 100
l
__________________________________________________________________________
1. Where a + b + c + d + e + f + g + h + i + j + k + l = 100, and
2. Where any one of a, b, c, etc. could be equal to zero or could assume
any convenient value from zero to 100, and thus the agent may be composed
of one alcohol, two alcohols, alcohol and a glycol, two glycols, three
glycols and alcohols, etc.
TABLE II
__________________________________________________________________________
EXAMPLES OF NON-IONIC SURFACTANTS USED
WITH ETHYLENE GLYCOL OR ANY ONE OR A
COMBINATION OF THE COMPOUNDS OF TABLE I
PERCENT OF SOLUTION BY WEIGHT
REAGENT
1 2 3 4 5 6 7 8 9 10
11
12
13
14
15
__________________________________________________________________________
Ethylene
100
95
90
80
70
50
20
95
90
80
70
60
80
80
a
Glycol
Surfynol
0 5 10
20
30
50
80
1 2 5 15
20
1 19
b
D.H. or
Dimethyl-
hexynediol
Nucleating
0 0 0 0 0 0 0 4 8 15
15
20
19
1 c
Compounds
__________________________________________________________________________
Where a + b + c = 100, and a, b, c can assume any convenient value as
illustrated above from 0-100.
Any one of the compounds or mixtures thereof of TABLE I can be substitute
for Ethylene glycol.
Any number of commercially available surfactants, such as listed
previously, can be substituted for Surfynol D.H. or for
Dimethylhexynediol.
Nucleating compounds could be any alcoholglycol soluble inorganic or
organic compound, or mixtures thereof, possessing the structural features
to collect water around it, and may include any of the organic or
inorganic compounds listed previously.
TABLE III
__________________________________________________________________________
PERCENT OF SOLUTION BY WEIGHT
REAGENT
1 2 3 4 5 6 7 8 9 10
11
12
13
14
15
__________________________________________________________________________
Ethylene
50
70
0 99.9
0 50
50
40
20
50
80
70
0 80
a
Glycol
Tetra- 50
0 70
0 99
0 0 40
50
20
0 0 70
0 b
ethylene
Glycol
G.A.F. 0 30
30
.1 1 40
30
10
20
20
1 10
10
19
c
Taurine-22
Nucleating
0 0 0 0 0 10
20
10
10
10
19
20
20
1 d
Compounds
such as NH.sub.4 I
or Phloro-
glucinol etc.
__________________________________________________________________________
Where a + b + c + d = 100, and a, b, c, d can assume any convenient value
as illustrated above from 0-100.
Any one of the compounds of TABLE I, or mixtures thereof, can be
substituted for Ethylene glycol tetraethyleneglycol.
Any surfactant, listed previously, or mixtures thereof can be substituted
for G.A.F. Taurine22
Nucleating compounds could be a pure organic or inorganic compound, such
as listed above, or any mixture of alcohol/glycol soluble inorganic salts
or organic compounds with appropriate structure.
TABLE IV
__________________________________________________________________________
EXAMPLES OF ANIONIC SURFACTANTS-SULFONATES
PERCENT OF SOLUTION BY WEIGHT
REAGENT 1 2 3 4 5 6 7 8 9 10
11
12
13
14
__________________________________________________________________________
Ethylene
90 90
90
40
80
80
90
70
50
0 0 0 0 a
Glycol
Tetra- 0 0 5 40
0 0 0 3 20
90
80
0 20
b
ethylene
Glycol
Isopropanol
5 0 0 0 10
0 0 2 5 0 0 80
0 c
Methanol
0 5 0 0 0 0 0 2 5 0 0 0 70
d
Alkyl 5 0 0 0 2 2 0 1 0 2 3 1 0 e
Sulfonate
Alkylaryl
0 5 0 0 2 2 0 1 5 2 3 2 0 f
Sulfonate
Alken- 0 0 5 5 2 2 0 1 3 2 0 3 0 g
alkynal-aryl
Sulfonate
Small chain
0 0 0 5 2 2 0 1 2 2 0 0 10
h
Sulfonate
Alkyl, 0 0 0 5 2 2 0 1 0 2 0 0 0 i
alkenyl,
alkynal-aryl
Phosphate
Nucleating
0 0 0 5 0 10
10
18
0 0 14
14
0 j
Compounds
CuBr.sub.2, CdI.sub.2,
CaCl.sub.2, NH.sub.4 I,
etc. Poloro-
glucinol,
EDTA, etc.
__________________________________________________________________________
Where a + b + c + d + e + f + g + h + i + j = 100, and
Where a, b, c, etc. can assume any convenient value from 0% to 100%, and
Where any alcohol, glycol or polyol can be used for any of the alcohols,
and
Where any anionic surfactant, sulfonate, carboxylate, alcoholate,
phosphate with unsubstituted, mono or polysubstituted carbon chain can be
substituted for the surfactantssulfonates listed above.
TABLE V
______________________________________
EXAMPLES OF CATIONIC SURFACTANTS
PERCENT OF SOLUTION BY WEIGHT
REAGENT 1 2 3 4 5 6 7 8 9 10 11
______________________________________
Ethylene 90 90 80 80 70 0 0 0 10 60 a
Glycol
Allyl 0 0 0 10 20 70 0 0 70 20 b
Alcohol
Tetraethylene
0 0 0 0 5 0 70 95 0 10 c
Glycol
Cationic 10 5 10 5 1 25 15 5 5 1 d
Surfactant e.g.
Quaternary
Ammonium salt,
amino derivative
or other
cationic feature
Nucleating 0 5 10 5 4 15 15 0 15 9 e
Compounds
______________________________________
Where a + b + c + d + e = 100, and
Where a, b, c etc. can assume any convenient value from 0 to 100, and
Where any alcohol, polyol, glycol listed in TABLE I or mixtures thereof
could be used for any alcohol listed, and
Any cationic surfactant, such as Trymeen Series of Emery, Taurine from
G.A.F. etc. can be substituted or used in conjunction with other
surfactants, and
Where the nucleating compound is any one of the abovelisted organic or
inorganic compounds, or mixtures thereof.
The testing of the various solutions set forth in the above tables was
effected as follows: A chamber was cooled to -80.degree. C. by a suitable
refrigerant which was passed into a jacket surrounding the chamber.
Nitrogen gas was fed through a coil immersed in a liquid nitrogen tank and
cooled to -80.degree. C. and then fed to the chamber. A combined steam and
agent nozzle was provided which included an agent jet located
concentrically within a steam jet such that the steam and agent were
simultaneously sprayed into the -80.degree. C. chamber containing
nitrogen, with the agent being forced from its nozzle by a suitable pump.
Ice crystals of a visually detectable size were not observed in the
chamber, even though the steam nozzle exhausted 100% water into the
-80.degree. C. nitrogen atmosphere. In another series of tests the flow
rate of cold gases were increased to Mach 0.6 level to simulate actual
flights of a jet plane and complete suppression of contrail was observed
at appropriate agent and engine power settings.
Briefly summarizing the foregoing, the agents for suppression of contrails
from the exhaust of a jet engine or plume of a rocket engine exhaust may
consist of mono, di, tri, tetra, and polyhydric alcohols chemically
referred as -ols, -diols (glycols), -triols, -tetra and -polyols. The
alcohols may be pure or mixtures or various compositions thereof. The
alcohol mixtures may further contain by weight, non-ionic, cationic,
anionic, or zwitterionic surfactants between 0.001% to 90% of the total
solution. Another solution may contain a mixture of surfactants or
cosurfactants of suitable concentrations which may vary from 0.001 to 90%,
1.0 to 50%, or 10 to 20% by weight of the total solution. Another solution
may contain ice nucleating organic compounds or inorganic nucleating salts
with cubic, rhombic, or hexagonal crystal structures such as ammonium
fluoride, ammonium iodide, calcium chloride, etc., which may or may not be
hygroscopes by themselves, in addition to surfactants in the mono, di,
tri, tetra, or polyhydric alcohols. The alcohols may have other functional
groups or structural features present in their structures. Appropriate
amounts of water or cosurfactants may be used to bring all the components
into a homogeneous solution.
While preferred embodiments of the present invention have been disclosed,
it will be appreciated that it is not limited thereto but may be otherwise
embodied within the scope of the following claims.
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